Recently, energetic developments and research have been made in various fields for effective utilization of sunlight energy with a view to meeting the requirement of saving energy.
I was quick to note the effective utilization of sunlight energy for illumination and have made various proposals. The most effective utilization of sunlight energy is to utilize sunlight energy in the form of light energy directly for illumination in the room without converting it to other forms of energy, such as electricity or heat.
In the known prior art there is proposed an apparatus capable of transmitting sunlight collected on the exterior of a house to a place where illumination is required, e.g., the interior of a room, by means of a light conductor. For this purpose, in the prior art, sunlight is concentrated by using a lens system, for example, a complicated arrangement of Fresnel lenses, and is introduced into the light conductor. In addition, since the above-mentioned apparatus is mainly intended to collect direct radiation of sunlight, it is necessary for said apparatus to operate precisely and smoothly to track the movement of the sun.
With this apparatus, the tracking mechanism of the apparatus is apt to become complicated, the positioning of the lens system is difficult, and the registering operation of the focus of the lens system with the inlet of the light conductor is quite dangerous, as well as requiring very great skill by the operator.
Other known prior arts have employed a parabolic reflector for concentrating direct radiation of sunlight at a focus point at which a light conductor is disposed. However, a parabolic reflector, in order to provide effective concentration, is comparatively large and requires a precise parabolic surface.
Thus, the optimum apparatus of this kinds was not achieved until the present.